freebsd-nq/lib/libthr/thread/thr_private.h

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/*
* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* Private thread definitions for the uthread kernel.
*
* $FreeBSD$
*/
#ifndef _THR_PRIVATE_H
#define _THR_PRIVATE_H
/*
* Evaluate the storage class specifier.
*/
#ifdef GLOBAL_PTHREAD_PRIVATE
#define SCLASS
#else
#define SCLASS extern
#endif
/*
* Include files.
*/
#include <sys/types.h>
#include <sys/cdefs.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/queue.h>
#include <pthread_np.h>
#include <sched.h>
#include <signal.h>
#include <spinlock.h>
#include <stdio.h>
#include <ucontext.h>
#include <unistd.h>
#if defined(_PTHREADS_INVARIANTS)
#include <assert.h>
#endif
#include <machine/atomic.h>
#include <sys/thr.h>
#include <sys/umtx.h>
#if defined(_PTHREADS_INVARIANTS)
/*
* Kernel fatal error handler macro.
*/
#define PANIC(string) \
do { \
_thread_printf(STDOUT_FILENO, (string)); \
_thread_printf(STDOUT_FILENO, \
"\nAbnormal termination, file: %s, line: %d\n", \
__FILE__, __LINE__); \
abort(); \
} while (0)
#define PTHREAD_ASSERT(cond, msg) do { \
if (!(cond)) \
PANIC(msg); \
} while (0)
#define PTHREAD_ASSERT_NOT_IN_SYNCQ(thrd) \
PTHREAD_ASSERT((((thrd)->flags & PTHREAD_FLAGS_IN_SYNCQ) == 0), \
"Illegal call from signal handler");
#else /* !_PTHREADS_INVARIANTS */
#define PANIC(string) _thread_exit(__FILE__, __LINE__, (string))
#define PTHREAD_ASSERT(cond, msg)
#define PTHREAD_ASSERT_NOT_IN_SYNCQ(thrd)
#endif /* _PTHREADS_INVARIANTS */
/* Output debug messages like this: */
#define stdout_debug(args...) _thread_printf(STDOUT_FILENO, args)
#define stderr_debug(args...) _thread_printf(STDOUT_FILENO, args)
/*
* Currently executing thread.
*/
#define curthread _get_curthread()
/*
* Locking macros
*/
#define UMTX_LOCK(m) \
do { \
if (umtx_lock((m), curthread->thr_id) != 0) \
abort(); \
} while (0)
#define UMTX_TRYLOCK(m, r) \
do { \
(r) = umtx_trylock((m), curthread->thr_id); \
if ((r) != 0 && (r) != EBUSY) \
abort(); \
} while (0)
#define UMTX_UNLOCK(m) \
do { \
if (umtx_unlock((m), curthread->thr_id) != 0) \
abort(); \
} while (0)
Make libthr async-signal-safe without costly signal masking. The guidlines I followed are: Only 3 functions (pthread_cancel, pthread_setcancelstate, pthread_setcanceltype) are required to be async-signal-safe by POSIX. None of the rest of the pthread api is required to be async-signal-safe. This means that only the three mentioned functions are safe to use from inside signal handlers. However, there are certain system/libc calls that are cancellation points that a caller may call from within a signal handler, and since they are cancellation points calls have to be made into libthr to test for cancellation and exit the thread if necessary. So, the cancellation test and thread exit code paths must be async-signal-safe as well. A summary of the changes follows: o Almost all of the code paths that masked signals, as well as locking the pthread structure now lock only the pthread structure. o Signals are masked (and left that way) as soon as a thread enters pthread_exit(). o The active and dead threads locks now explicitly require that signals are masked. o Access to the isdead field of the pthread structure is protected by both the active and dead list locks for writing. Either one is sufficient for reading. o The thread state and type fields have been combined into one three-state switch to make it easier to read without requiring a lock. It doesn't need a lock for writing (and therefore for reading either) because only the current thread can write to it and it is an integer value. o The thread state field of the pthread structure has been eliminated. It was an unnecessary field that mostly duplicated the flags field, but required additional locking that would make a lot more code paths require signal masking. Any truly unique values (such as PS_DEAD) have been reborn as separate members of the pthread structure. o Since the mutex and condvar pthread functions are not async-signal-safe there is no need to muck about with the wait queues when handling a signal ... o ... which also removes the need for wrapping signal handlers and sigaction(2). o The condvar and mutex async-cancellation code had to be revised as a result of some of these changes, which resulted in semi-unrelated changes which would have been difficult to work on as a separate commit, so they are included as well. The only part of the changes I am worried about is related to locking for the pthread joining fields. But, I will take a closer look at them once this mega-patch is committed.
2004-05-20 12:06:16 +00:00
#define PTHREAD_LOCK(p) UMTX_LOCK(&(p)->lock)
#define PTHREAD_UNLOCK(p) UMTX_UNLOCK(&(p)->lock)
Make libthr async-signal-safe without costly signal masking. The guidlines I followed are: Only 3 functions (pthread_cancel, pthread_setcancelstate, pthread_setcanceltype) are required to be async-signal-safe by POSIX. None of the rest of the pthread api is required to be async-signal-safe. This means that only the three mentioned functions are safe to use from inside signal handlers. However, there are certain system/libc calls that are cancellation points that a caller may call from within a signal handler, and since they are cancellation points calls have to be made into libthr to test for cancellation and exit the thread if necessary. So, the cancellation test and thread exit code paths must be async-signal-safe as well. A summary of the changes follows: o Almost all of the code paths that masked signals, as well as locking the pthread structure now lock only the pthread structure. o Signals are masked (and left that way) as soon as a thread enters pthread_exit(). o The active and dead threads locks now explicitly require that signals are masked. o Access to the isdead field of the pthread structure is protected by both the active and dead list locks for writing. Either one is sufficient for reading. o The thread state and type fields have been combined into one three-state switch to make it easier to read without requiring a lock. It doesn't need a lock for writing (and therefore for reading either) because only the current thread can write to it and it is an integer value. o The thread state field of the pthread structure has been eliminated. It was an unnecessary field that mostly duplicated the flags field, but required additional locking that would make a lot more code paths require signal masking. Any truly unique values (such as PS_DEAD) have been reborn as separate members of the pthread structure. o Since the mutex and condvar pthread functions are not async-signal-safe there is no need to muck about with the wait queues when handling a signal ... o ... which also removes the need for wrapping signal handlers and sigaction(2). o The condvar and mutex async-cancellation code had to be revised as a result of some of these changes, which resulted in semi-unrelated changes which would have been difficult to work on as a separate commit, so they are included as well. The only part of the changes I am worried about is related to locking for the pthread joining fields. But, I will take a closer look at them once this mega-patch is committed.
2004-05-20 12:06:16 +00:00
#define PTHREAD_WAKE(ptd) thr_wake((ptd)->thr_id)
/*
* TailQ initialization values.
*/
#define TAILQ_INITIALIZER { NULL, NULL }
#define UMTX_INITIALIZER { NULL }
struct pthread_mutex_attr {
enum pthread_mutextype m_type;
int m_protocol;
int m_ceiling;
long m_flags;
};
/*
* Static mutex initialization values.
*/
#define PTHREAD_MUTEXATTR_STATIC_INITIALIZER \
{ PTHREAD_MUTEX_DEFAULT, PTHREAD_PRIO_NONE, 0, MUTEX_FLAGS_PRIVATE }
#define PTHREAD_MUTEX_STATIC_INITIALIZER \
{ PTHREAD_MUTEXATTR_STATIC_INITIALIZER, UMTX_INITIALIZER, NULL, \
0, 0, TAILQ_INITIALIZER }
union pthread_mutex_data {
void *m_ptr;
int m_count;
};
struct pthread_mutex {
enum pthread_mutextype m_type;
int m_protocol;
TAILQ_HEAD(mutex_head, pthread) m_queue;
struct pthread *m_owner;
union pthread_mutex_data m_data;
long m_flags;
int m_refcount;
/*
* Used for priority inheritence and protection.
*
* m_prio - For priority inheritence, the highest active
* priority (threads locking the mutex inherit
* this priority). For priority protection, the
* ceiling priority of this mutex.
* m_saved_prio - mutex owners inherited priority before
* taking the mutex, restored when the owner
* unlocks the mutex.
*/
int m_prio;
int m_saved_prio;
/*
* Link for list of all mutexes a thread currently owns.
*/
TAILQ_ENTRY(pthread_mutex) m_qe;
/*
* Lock for accesses to this structure.
*/
spinlock_t lock;
};
struct pthread_spinlock {
void *s_owner;
unsigned int s_magic;
};
/*
* Flags for mutexes.
*/
#define MUTEX_FLAGS_PRIVATE 0x01
#define MUTEX_FLAGS_INITED 0x02
#define MUTEX_FLAGS_BUSY 0x04
/*
* Condition variable definitions.
*/
enum pthread_cond_type {
COND_TYPE_FAST,
COND_TYPE_MAX
};
struct pthread_cond {
enum pthread_cond_type c_type;
TAILQ_HEAD(cond_head, pthread) c_queue;
pthread_mutex_t c_mutex;
void *c_data;
long c_flags;
int c_seqno;
/*
* Lock for accesses to this structure.
*/
struct umtx c_lock;
};
struct pthread_cond_attr {
enum pthread_cond_type c_type;
long c_flags;
};
/*
* Flags for condition variables.
*/
#define COND_FLAGS_INITED 0x01
/*
* Static cond initialization values.
*/
#define PTHREAD_COND_STATIC_INITIALIZER \
{ COND_TYPE_FAST, TAILQ_INITIALIZER, NULL, NULL, \
0, 0, UMTX_INITIALIZER }
/*
* Semaphore definitions.
*/
struct sem {
#define SEM_MAGIC ((u_int32_t) 0x09fa4012)
u_int32_t magic;
pthread_mutex_t lock;
pthread_cond_t gtzero;
u_int32_t count;
u_int32_t nwaiters;
};
/*
* Cleanup definitions.
*/
struct pthread_cleanup {
struct pthread_cleanup *next;
void (*routine) ();
void *routine_arg;
};
struct pthread_attr {
int sched_policy;
int sched_inherit;
int sched_interval;
int prio;
int suspend;
int flags;
void *arg_attr;
void (*cleanup_attr) ();
void *stackaddr_attr;
size_t stacksize_attr;
size_t guardsize_attr;
};
/*
* Thread creation state attributes.
*/
#define PTHREAD_CREATE_RUNNING 0
#define PTHREAD_CREATE_SUSPENDED 1
/*
* Miscellaneous definitions.
*/
#define PTHREAD_STACK_DEFAULT 65536
/*
* Size of default red zone at the end of each stack. In actuality, this "red
* zone" is merely an unmapped region, except in the case of the initial stack.
* Since mmap() makes it possible to specify the maximum growth of a MAP_STACK
* region, an unmapped gap between thread stacks achieves the same effect as
* explicitly mapped red zones.
* This is declared and initialized in uthread_init.c.
*/
extern int _pthread_guard_default;
extern int _pthread_page_size;
/*
* Maximum size of initial thread's stack. This perhaps deserves to be larger
* than the stacks of other threads, since many applications are likely to run
* almost entirely on this stack.
*/
#define PTHREAD_STACK_INITIAL 0x100000
/*
* Define the different priority ranges. All applications have thread
* priorities constrained within 0-31. The threads library raises the
* priority when delivering signals in order to ensure that signal
* delivery happens (from the POSIX spec) "as soon as possible".
* In the future, the threads library will also be able to map specific
* threads into real-time (cooperating) processes or kernel threads.
* The RT and SIGNAL priorities will be used internally and added to
* thread base priorities so that the scheduling queue can handle both
* normal and RT priority threads with and without signal handling.
*
* The approach taken is that, within each class, signal delivery
* always has priority over thread execution.
*/
#define PTHREAD_DEFAULT_PRIORITY 15
#define PTHREAD_MIN_PRIORITY 0
#define PTHREAD_MAX_PRIORITY 31 /* 0x1F */
#define PTHREAD_SIGNAL_PRIORITY 32 /* 0x20 */
#define PTHREAD_RT_PRIORITY 64 /* 0x40 */
#define PTHREAD_FIRST_PRIORITY PTHREAD_MIN_PRIORITY
#define PTHREAD_LAST_PRIORITY \
(PTHREAD_MAX_PRIORITY + PTHREAD_SIGNAL_PRIORITY + PTHREAD_RT_PRIORITY)
#define PTHREAD_BASE_PRIORITY(prio) ((prio) & PTHREAD_MAX_PRIORITY)
/*
* Clock resolution in microseconds.
*/
#define CLOCK_RES_USEC 10000
#define CLOCK_RES_USEC_MIN 1000
/*
* Time slice period in microseconds.
*/
#define TIMESLICE_USEC 20000
/*
* XXX Define a thread-safe macro to get the current time of day
* which is updated at regular intervals by the scheduling signal
* handler.
*/
#define GET_CURRENT_TOD(tv) gettimeofday(&(tv), NULL)
struct pthread_barrierattr {
int ba_pshared;
};
/*
* POSIX Threads barrier object.
* Lock order:
* 1. pthread_barrier
* 2. pthread
*/
struct pthread_barrier {
TAILQ_HEAD(barrq_head, pthread) b_barrq;
struct umtx b_lock;
int b_total;
int b_subtotal;
};
struct pthread_rwlockattr {
int pshared;
};
struct pthread_rwlock {
pthread_mutex_t lock; /* monitor lock */
int state; /* 0 = idle >0 = # of readers -1 = writer */
pthread_cond_t read_signal;
pthread_cond_t write_signal;
int blocked_writers;
};
/*
* Thread states.
*/
enum pthread_state {
PS_RUNNING,
PS_MUTEX_WAIT,
PS_COND_WAIT,
PS_BARRIER_WAIT,
PS_SLEEP_WAIT, /* XXX We need to wrap syscalls to set this state */
PS_WAIT_WAIT,
PS_JOIN,
PS_DEAD,
PS_DEADLOCK,
PS_STATE_MAX
};
/*
* File descriptor locking definitions.
*/
#define FD_READ 0x1
#define FD_WRITE 0x2
#define FD_RDWR (FD_READ | FD_WRITE)
union pthread_wait_data {
pthread_mutex_t mutex;
pthread_cond_t cond;
spinlock_t *spinlock;
struct pthread *thread;
};
struct join_status {
struct pthread *thread;
void *ret;
int error;
};
struct pthread_state_data {
union pthread_wait_data psd_wait_data;
enum pthread_state psd_state;
int psd_flags;
};
struct pthread_specific_elem {
const void *data;
int seqno;
};
struct rwlock_held {
LIST_ENTRY(rwlock_held) rh_link;
struct pthread_rwlock *rh_rwlock;
int rh_rdcount;
int rh_wrcount;
};
LIST_HEAD(rwlock_listhead, rwlock_held);
Make libthr async-signal-safe without costly signal masking. The guidlines I followed are: Only 3 functions (pthread_cancel, pthread_setcancelstate, pthread_setcanceltype) are required to be async-signal-safe by POSIX. None of the rest of the pthread api is required to be async-signal-safe. This means that only the three mentioned functions are safe to use from inside signal handlers. However, there are certain system/libc calls that are cancellation points that a caller may call from within a signal handler, and since they are cancellation points calls have to be made into libthr to test for cancellation and exit the thread if necessary. So, the cancellation test and thread exit code paths must be async-signal-safe as well. A summary of the changes follows: o Almost all of the code paths that masked signals, as well as locking the pthread structure now lock only the pthread structure. o Signals are masked (and left that way) as soon as a thread enters pthread_exit(). o The active and dead threads locks now explicitly require that signals are masked. o Access to the isdead field of the pthread structure is protected by both the active and dead list locks for writing. Either one is sufficient for reading. o The thread state and type fields have been combined into one three-state switch to make it easier to read without requiring a lock. It doesn't need a lock for writing (and therefore for reading either) because only the current thread can write to it and it is an integer value. o The thread state field of the pthread structure has been eliminated. It was an unnecessary field that mostly duplicated the flags field, but required additional locking that would make a lot more code paths require signal masking. Any truly unique values (such as PS_DEAD) have been reborn as separate members of the pthread structure. o Since the mutex and condvar pthread functions are not async-signal-safe there is no need to muck about with the wait queues when handling a signal ... o ... which also removes the need for wrapping signal handlers and sigaction(2). o The condvar and mutex async-cancellation code had to be revised as a result of some of these changes, which resulted in semi-unrelated changes which would have been difficult to work on as a separate commit, so they are included as well. The only part of the changes I am worried about is related to locking for the pthread joining fields. But, I will take a closer look at them once this mega-patch is committed.
2004-05-20 12:06:16 +00:00
/*
* The cancel mode a thread is in is determined by the
* the cancel type and state it is set in. The two values
* are combined into one mode:
* Mode State Type
* ---- ----- ----
* off disabled deferred
* off disabled async
* deferred enabled deferred
* async enabled async
*/
enum cancel_mode { M_OFF, M_DEFERRED, M_ASYNC };
/*
* A thread's cancellation is pending until the cancel
* mode has been tested to determine if the thread can be
* cancelled immediately.
*/
enum cancellation_state { CS_NULL, CS_PENDING, CS_SET };
/*
* Thread structure.
*/
struct pthread {
/*
* Magic value to help recognize a valid thread structure
* from an invalid one:
*/
#define PTHREAD_MAGIC ((u_int32_t) 0xd09ba115)
u_int32_t magic;
char *name;
u_int64_t uniqueid; /* for gdb */
thr_id_t thr_id;
sigset_t savedsig;
int signest; /* blocked signal netsting level */
Make libthr async-signal-safe without costly signal masking. The guidlines I followed are: Only 3 functions (pthread_cancel, pthread_setcancelstate, pthread_setcanceltype) are required to be async-signal-safe by POSIX. None of the rest of the pthread api is required to be async-signal-safe. This means that only the three mentioned functions are safe to use from inside signal handlers. However, there are certain system/libc calls that are cancellation points that a caller may call from within a signal handler, and since they are cancellation points calls have to be made into libthr to test for cancellation and exit the thread if necessary. So, the cancellation test and thread exit code paths must be async-signal-safe as well. A summary of the changes follows: o Almost all of the code paths that masked signals, as well as locking the pthread structure now lock only the pthread structure. o Signals are masked (and left that way) as soon as a thread enters pthread_exit(). o The active and dead threads locks now explicitly require that signals are masked. o Access to the isdead field of the pthread structure is protected by both the active and dead list locks for writing. Either one is sufficient for reading. o The thread state and type fields have been combined into one three-state switch to make it easier to read without requiring a lock. It doesn't need a lock for writing (and therefore for reading either) because only the current thread can write to it and it is an integer value. o The thread state field of the pthread structure has been eliminated. It was an unnecessary field that mostly duplicated the flags field, but required additional locking that would make a lot more code paths require signal masking. Any truly unique values (such as PS_DEAD) have been reborn as separate members of the pthread structure. o Since the mutex and condvar pthread functions are not async-signal-safe there is no need to muck about with the wait queues when handling a signal ... o ... which also removes the need for wrapping signal handlers and sigaction(2). o The condvar and mutex async-cancellation code had to be revised as a result of some of these changes, which resulted in semi-unrelated changes which would have been difficult to work on as a separate commit, so they are included as well. The only part of the changes I am worried about is related to locking for the pthread joining fields. But, I will take a closer look at them once this mega-patch is committed.
2004-05-20 12:06:16 +00:00
int ptdflags; /* used by other other threads
to signal this thread */
int isdead;
int isdeadlocked;
int exiting;
int cancellationpoint;
/*
* Lock for accesses to this thread structure.
*/
struct umtx lock;
/* Queue entry for list of all threads: */
TAILQ_ENTRY(pthread) tle;
/* Queue entry for list of dead threads: */
TAILQ_ENTRY(pthread) dle;
/*
* Thread start routine, argument, stack pointer and thread
* attributes.
*/
void *(*start_routine)(void *);
void *arg;
void *stack;
struct pthread_attr attr;
/*
* Machine context, including signal state.
*/
ucontext_t ctx;
/*
Make libthr async-signal-safe without costly signal masking. The guidlines I followed are: Only 3 functions (pthread_cancel, pthread_setcancelstate, pthread_setcanceltype) are required to be async-signal-safe by POSIX. None of the rest of the pthread api is required to be async-signal-safe. This means that only the three mentioned functions are safe to use from inside signal handlers. However, there are certain system/libc calls that are cancellation points that a caller may call from within a signal handler, and since they are cancellation points calls have to be made into libthr to test for cancellation and exit the thread if necessary. So, the cancellation test and thread exit code paths must be async-signal-safe as well. A summary of the changes follows: o Almost all of the code paths that masked signals, as well as locking the pthread structure now lock only the pthread structure. o Signals are masked (and left that way) as soon as a thread enters pthread_exit(). o The active and dead threads locks now explicitly require that signals are masked. o Access to the isdead field of the pthread structure is protected by both the active and dead list locks for writing. Either one is sufficient for reading. o The thread state and type fields have been combined into one three-state switch to make it easier to read without requiring a lock. It doesn't need a lock for writing (and therefore for reading either) because only the current thread can write to it and it is an integer value. o The thread state field of the pthread structure has been eliminated. It was an unnecessary field that mostly duplicated the flags field, but required additional locking that would make a lot more code paths require signal masking. Any truly unique values (such as PS_DEAD) have been reborn as separate members of the pthread structure. o Since the mutex and condvar pthread functions are not async-signal-safe there is no need to muck about with the wait queues when handling a signal ... o ... which also removes the need for wrapping signal handlers and sigaction(2). o The condvar and mutex async-cancellation code had to be revised as a result of some of these changes, which resulted in semi-unrelated changes which would have been difficult to work on as a separate commit, so they are included as well. The only part of the changes I am worried about is related to locking for the pthread joining fields. But, I will take a closer look at them once this mega-patch is committed.
2004-05-20 12:06:16 +00:00
* The primary method of obtaining a thread's cancel state
* and type is through cancelmode. The cancelstate field is
* only so we don't loose the cancel state when the mode is
* turned off.
*/
Make libthr async-signal-safe without costly signal masking. The guidlines I followed are: Only 3 functions (pthread_cancel, pthread_setcancelstate, pthread_setcanceltype) are required to be async-signal-safe by POSIX. None of the rest of the pthread api is required to be async-signal-safe. This means that only the three mentioned functions are safe to use from inside signal handlers. However, there are certain system/libc calls that are cancellation points that a caller may call from within a signal handler, and since they are cancellation points calls have to be made into libthr to test for cancellation and exit the thread if necessary. So, the cancellation test and thread exit code paths must be async-signal-safe as well. A summary of the changes follows: o Almost all of the code paths that masked signals, as well as locking the pthread structure now lock only the pthread structure. o Signals are masked (and left that way) as soon as a thread enters pthread_exit(). o The active and dead threads locks now explicitly require that signals are masked. o Access to the isdead field of the pthread structure is protected by both the active and dead list locks for writing. Either one is sufficient for reading. o The thread state and type fields have been combined into one three-state switch to make it easier to read without requiring a lock. It doesn't need a lock for writing (and therefore for reading either) because only the current thread can write to it and it is an integer value. o The thread state field of the pthread structure has been eliminated. It was an unnecessary field that mostly duplicated the flags field, but required additional locking that would make a lot more code paths require signal masking. Any truly unique values (such as PS_DEAD) have been reborn as separate members of the pthread structure. o Since the mutex and condvar pthread functions are not async-signal-safe there is no need to muck about with the wait queues when handling a signal ... o ... which also removes the need for wrapping signal handlers and sigaction(2). o The condvar and mutex async-cancellation code had to be revised as a result of some of these changes, which resulted in semi-unrelated changes which would have been difficult to work on as a separate commit, so they are included as well. The only part of the changes I am worried about is related to locking for the pthread joining fields. But, I will take a closer look at them once this mega-patch is committed.
2004-05-20 12:06:16 +00:00
enum cancel_mode cancelmode;
enum cancel_mode cancelstate;
Make libthr async-signal-safe without costly signal masking. The guidlines I followed are: Only 3 functions (pthread_cancel, pthread_setcancelstate, pthread_setcanceltype) are required to be async-signal-safe by POSIX. None of the rest of the pthread api is required to be async-signal-safe. This means that only the three mentioned functions are safe to use from inside signal handlers. However, there are certain system/libc calls that are cancellation points that a caller may call from within a signal handler, and since they are cancellation points calls have to be made into libthr to test for cancellation and exit the thread if necessary. So, the cancellation test and thread exit code paths must be async-signal-safe as well. A summary of the changes follows: o Almost all of the code paths that masked signals, as well as locking the pthread structure now lock only the pthread structure. o Signals are masked (and left that way) as soon as a thread enters pthread_exit(). o The active and dead threads locks now explicitly require that signals are masked. o Access to the isdead field of the pthread structure is protected by both the active and dead list locks for writing. Either one is sufficient for reading. o The thread state and type fields have been combined into one three-state switch to make it easier to read without requiring a lock. It doesn't need a lock for writing (and therefore for reading either) because only the current thread can write to it and it is an integer value. o The thread state field of the pthread structure has been eliminated. It was an unnecessary field that mostly duplicated the flags field, but required additional locking that would make a lot more code paths require signal masking. Any truly unique values (such as PS_DEAD) have been reborn as separate members of the pthread structure. o Since the mutex and condvar pthread functions are not async-signal-safe there is no need to muck about with the wait queues when handling a signal ... o ... which also removes the need for wrapping signal handlers and sigaction(2). o The condvar and mutex async-cancellation code had to be revised as a result of some of these changes, which resulted in semi-unrelated changes which would have been difficult to work on as a separate commit, so they are included as well. The only part of the changes I am worried about is related to locking for the pthread joining fields. But, I will take a closer look at them once this mega-patch is committed.
2004-05-20 12:06:16 +00:00
/* Specifies if cancellation is pending, acted upon, or neither. */
enum cancellation_state cancellation;
/*
* Error variable used instead of errno. The function __error()
* returns a pointer to this.
*/
int error;
/*
* The joiner is the thread that is joining to this thread. The
* join status keeps track of a join operation to another thread.
*/
struct pthread *joiner;
struct join_status join_status;
/*
* A thread can belong to:
*
* o A queue of threads waiting for a mutex
* o A queue of threads waiting for a condition variable
*
* A thread can also be joining a thread (the joiner field above).
*
* Use sqe for synchronization (mutex and condition variable) queue
* links.
*/
TAILQ_ENTRY(pthread) sqe; /* synchronization queue link */
/* Wait data. */
union pthread_wait_data data;
/* Miscellaneous flags; only set with signals deferred. */
int flags;
#define PTHREAD_FLAGS_PRIVATE 0x0001
#define PTHREAD_FLAGS_BARR_REL 0x0004 /* has been released from barrier */
Make libthr async-signal-safe without costly signal masking. The guidlines I followed are: Only 3 functions (pthread_cancel, pthread_setcancelstate, pthread_setcanceltype) are required to be async-signal-safe by POSIX. None of the rest of the pthread api is required to be async-signal-safe. This means that only the three mentioned functions are safe to use from inside signal handlers. However, there are certain system/libc calls that are cancellation points that a caller may call from within a signal handler, and since they are cancellation points calls have to be made into libthr to test for cancellation and exit the thread if necessary. So, the cancellation test and thread exit code paths must be async-signal-safe as well. A summary of the changes follows: o Almost all of the code paths that masked signals, as well as locking the pthread structure now lock only the pthread structure. o Signals are masked (and left that way) as soon as a thread enters pthread_exit(). o The active and dead threads locks now explicitly require that signals are masked. o Access to the isdead field of the pthread structure is protected by both the active and dead list locks for writing. Either one is sufficient for reading. o The thread state and type fields have been combined into one three-state switch to make it easier to read without requiring a lock. It doesn't need a lock for writing (and therefore for reading either) because only the current thread can write to it and it is an integer value. o The thread state field of the pthread structure has been eliminated. It was an unnecessary field that mostly duplicated the flags field, but required additional locking that would make a lot more code paths require signal masking. Any truly unique values (such as PS_DEAD) have been reborn as separate members of the pthread structure. o Since the mutex and condvar pthread functions are not async-signal-safe there is no need to muck about with the wait queues when handling a signal ... o ... which also removes the need for wrapping signal handlers and sigaction(2). o The condvar and mutex async-cancellation code had to be revised as a result of some of these changes, which resulted in semi-unrelated changes which would have been difficult to work on as a separate commit, so they are included as well. The only part of the changes I am worried about is related to locking for the pthread joining fields. But, I will take a closer look at them once this mega-patch is committed.
2004-05-20 12:06:16 +00:00
#define PTHREAD_FLAGS_IN_BARRQ 0x0008 /* in barrier queue using sqe link */
#define PTHREAD_FLAGS_IN_CONDQ 0x0080 /* in condition queue using sqe link*/
#define PTHREAD_FLAGS_IN_MUTEXQ 0x0100 /* in mutex queue using sqe link */
#define PTHREAD_FLAGS_SUSPENDED 0x0200 /* thread is suspended */
#define PTHREAD_FLAGS_TRACE 0x0400 /* for debugging purposes */
#define PTHREAD_FLAGS_IN_SYNCQ \
Make libthr async-signal-safe without costly signal masking. The guidlines I followed are: Only 3 functions (pthread_cancel, pthread_setcancelstate, pthread_setcanceltype) are required to be async-signal-safe by POSIX. None of the rest of the pthread api is required to be async-signal-safe. This means that only the three mentioned functions are safe to use from inside signal handlers. However, there are certain system/libc calls that are cancellation points that a caller may call from within a signal handler, and since they are cancellation points calls have to be made into libthr to test for cancellation and exit the thread if necessary. So, the cancellation test and thread exit code paths must be async-signal-safe as well. A summary of the changes follows: o Almost all of the code paths that masked signals, as well as locking the pthread structure now lock only the pthread structure. o Signals are masked (and left that way) as soon as a thread enters pthread_exit(). o The active and dead threads locks now explicitly require that signals are masked. o Access to the isdead field of the pthread structure is protected by both the active and dead list locks for writing. Either one is sufficient for reading. o The thread state and type fields have been combined into one three-state switch to make it easier to read without requiring a lock. It doesn't need a lock for writing (and therefore for reading either) because only the current thread can write to it and it is an integer value. o The thread state field of the pthread structure has been eliminated. It was an unnecessary field that mostly duplicated the flags field, but required additional locking that would make a lot more code paths require signal masking. Any truly unique values (such as PS_DEAD) have been reborn as separate members of the pthread structure. o Since the mutex and condvar pthread functions are not async-signal-safe there is no need to muck about with the wait queues when handling a signal ... o ... which also removes the need for wrapping signal handlers and sigaction(2). o The condvar and mutex async-cancellation code had to be revised as a result of some of these changes, which resulted in semi-unrelated changes which would have been difficult to work on as a separate commit, so they are included as well. The only part of the changes I am worried about is related to locking for the pthread joining fields. But, I will take a closer look at them once this mega-patch is committed.
2004-05-20 12:06:16 +00:00
(PTHREAD_FLAGS_IN_CONDQ | PTHREAD_FLAGS_IN_MUTEXQ | PTHREAD_FLAGS_IN_BARRQ)
#define PTHREAD_FLAGS_NOT_RUNNING \
(PTHREAD_FLAGS_IN_SYNCQ | PTHREAD_FLAGS_SUSPENDED)
/*
* Base priority is the user setable and retrievable priority
* of the thread. It is only affected by explicit calls to
* set thread priority and upon thread creation via a thread
* attribute or default priority.
*/
char base_priority;
/*
* Inherited priority is the priority a thread inherits by
* taking a priority inheritence or protection mutex. It
* is not affected by base priority changes. Inherited
* priority defaults to and remains 0 until a mutex is taken
* that is being waited on by any other thread whose priority
* is non-zero.
*/
char inherited_priority;
/*
* Active priority is always the maximum of the threads base
* priority and inherited priority. When there is a change
* in either the base or inherited priority, the active
* priority must be recalculated.
*/
char active_priority;
/* Number of priority ceiling or protection mutexes owned. */
int prio_inherit_count;
int prio_protect_count;
/*
* Queue of currently owned mutexes.
*/
TAILQ_HEAD(, pthread_mutex) mutexq;
/*
* List of read-write locks owned for reading _OR_ writing.
* This is accessed only by the current thread, so there's
* no need for mutual exclusion.
*/
struct rwlock_listhead *rwlockList;
void *ret;
struct pthread_specific_elem *specific;
int specific_data_count;
/*
* Architecture specific id field used for _{get, set}_curthread()
* interface.
*/
void *arch_id;
/* Cleanup handlers Link List */
struct pthread_cleanup *cleanup;
char *fname; /* Ptr to source file name */
int lineno; /* Source line number. */
};
/*
* Global variables for the uthread kernel.
*/
SCLASS void *_usrstack
#ifdef GLOBAL_PTHREAD_PRIVATE
= (void *) USRSTACK;
#else
;
#endif
SCLASS spinlock_t stack_lock
#ifdef GLOBAL_PTHREAD_PRIVATE
= _SPINLOCK_INITIALIZER
#endif
;
#define STACK_LOCK _SPINLOCK(&stack_lock);
#define STACK_UNLOCK _SPINUNLOCK(&stack_lock);
/* List of all threads: */
SCLASS TAILQ_HEAD(, pthread) _thread_list
#ifdef GLOBAL_PTHREAD_PRIVATE
= TAILQ_HEAD_INITIALIZER(_thread_list);
#else
;
#endif
/* Dead threads: */
SCLASS TAILQ_HEAD(, pthread) _dead_list
#ifdef GLOBAL_PTHREAD_PRIVATE
= TAILQ_HEAD_INITIALIZER(_dead_list);
#else
;
#endif
/*
* These two locks protect the global active threads list and
* the global dead threads list, respectively. Combining these
* into one lock for both lists doesn't seem wise, since it
* would likely increase contention during busy thread creation
* and destruction for very little savings in space.
*
* The lock for the "dead threads list" must be a pthread mutex
* because it is used with condition variables to synchronize
* the gc thread with active threads in the process of exiting or
* dead threads who have just been joined.
*/
SCLASS spinlock_t thread_list_lock
#ifdef GLOBAL_PTHREAD_PRIVATE
= _SPINLOCK_INITIALIZER
#endif
;
SCLASS pthread_mutex_t dead_list_lock
#ifdef GLOBAL_PTHREAD_PRIVATE
= NULL
#endif
;
#define THREAD_LIST_LOCK _SPINLOCK(&thread_list_lock)
#define THREAD_LIST_UNLOCK _SPINUNLOCK(&thread_list_lock)
#define DEAD_LIST_LOCK _pthread_mutex_lock(&dead_list_lock)
#define DEAD_LIST_UNLOCK _pthread_mutex_unlock(&dead_list_lock)
/* Initial thread: */
SCLASS struct pthread *_thread_initial
#ifdef GLOBAL_PTHREAD_PRIVATE
= NULL;
#else
;
#endif
/* Default thread attributes: */
SCLASS struct pthread_attr pthread_attr_default
#ifdef GLOBAL_PTHREAD_PRIVATE
= { SCHED_RR, 0, TIMESLICE_USEC, PTHREAD_DEFAULT_PRIORITY,
PTHREAD_CREATE_RUNNING, PTHREAD_CREATE_JOINABLE, NULL, NULL, NULL,
PTHREAD_STACK_DEFAULT, -1 };
#else
;
#endif
/* Default mutex attributes: */
SCLASS struct pthread_mutex_attr pthread_mutexattr_default
#ifdef GLOBAL_PTHREAD_PRIVATE
= { PTHREAD_MUTEX_DEFAULT, PTHREAD_PRIO_NONE, 0, 0 };
#else
;
#endif
/* Default condition variable attributes: */
SCLASS struct pthread_cond_attr pthread_condattr_default
#ifdef GLOBAL_PTHREAD_PRIVATE
= { COND_TYPE_FAST, 0 };
#else
;
#endif
/*
* Array of signal actions for this process.
*/
SCLASS struct sigaction _thread_sigact[NSIG];
/* Precomputed signal set for _thread_suspend. */
SCLASS sigset_t _thread_suspend_sigset;
/* Tracks the number of threads blocked while waiting for a spinlock. */
SCLASS volatile int _spinblock_count
#ifdef GLOBAL_PTHREAD_PRIVATE
= 0
#endif
;
/* Undefine the storage class specifier: */
#undef SCLASS
/*
* Function prototype definitions.
*/
__BEGIN_DECLS
char *__ttyname_basic(int);
char *__ttyname_r_basic(int, char *, size_t);
char *ttyname_r(int, char *, size_t);
void _cond_wait_backout(pthread_t);
int _find_thread(pthread_t);
pthread_t _get_curthread(void);
void *_set_curthread(ucontext_t *, struct pthread *, int *);
void _retire_thread(void *arch_id);
void *_thread_stack_alloc(size_t, size_t);
void _thread_stack_free(void *, size_t, size_t);
int _thread_create(pthread_t *,const pthread_attr_t *,void *(*start_routine)(void *),void *,pthread_t);
int _mutex_cv_lock(pthread_mutex_t *);
int _mutex_cv_unlock(pthread_mutex_t *);
void _mutex_lock_backout(pthread_t);
void _mutex_notify_priochange(pthread_t);
int _mutex_reinit(pthread_mutex_t *);
void _mutex_unlock_private(pthread_t);
int _cond_reinit(pthread_cond_t *);
void *_pthread_getspecific(pthread_key_t);
int _pthread_key_create(pthread_key_t *, void (*) (void *));
int _pthread_key_delete(pthread_key_t);
int _pthread_mutex_destroy(pthread_mutex_t *);
int _pthread_mutex_init(pthread_mutex_t *, const pthread_mutexattr_t *);
int _pthread_mutex_lock(pthread_mutex_t *);
int _pthread_mutex_trylock(pthread_mutex_t *);
int _pthread_mutex_unlock(pthread_mutex_t *);
int _pthread_mutexattr_init(pthread_mutexattr_t *);
int _pthread_mutexattr_destroy(pthread_mutexattr_t *);
int _pthread_mutexattr_settype(pthread_mutexattr_t *, int);
int _pthread_once(pthread_once_t *, void (*) (void));
pthread_t _pthread_self(void);
int _pthread_setspecific(pthread_key_t, const void *);
int _spintrylock(spinlock_t *);
void _thread_exit(char *, int, char *);
void _thread_exit_cleanup(void);
void *_thread_cleanup(pthread_t);
void _thread_cleanupspecific(void);
void _thread_dump_info(void);
void _thread_init(void);
void _thread_printf(int fd, const char *, ...);
void _thread_start(void);
void _thread_seterrno(pthread_t, int);
void _thread_enter_cancellation_point(void);
void _thread_leave_cancellation_point(void);
void _thread_cancellation_point(void);
int _thread_suspend(pthread_t thread, const struct timespec *abstime);
2003-05-12 10:34:01 +00:00
void _thread_critical_enter(pthread_t);
void _thread_critical_exit(pthread_t);
void _thread_sigblock();
void _thread_sigunblock();
void adjust_prio_inheritance(struct pthread *);
void adjust_prio_protection(struct pthread *);
void deadlist_free_onethread(struct pthread *);
void init_td_common(struct pthread *, struct pthread_attr *, int);
void init_tdlist(struct pthread *, int);
void proc_sigact_copyin(int, const struct sigaction *);
void proc_sigact_copyout(int, struct sigaction *);
void readjust_priorities(struct pthread *, struct pthread_mutex *);
struct sigaction *proc_sigact_sigaction(int);
/* #include <sys/aio.h> */
#ifdef _SYS_AIO_H_
int __sys_aio_suspend(const struct aiocb * const[], int, const struct timespec *);
#endif
/* #include <sys/event.h> */
#ifdef _SYS_EVENT_H_
int __sys_kevent(int, const struct kevent *, int, struct kevent *,
int, const struct timespec *);
#endif
/* #include <sys/ioctl.h> */
#ifdef _SYS_IOCTL_H_
int __sys_ioctl(int, unsigned long, ...);
#endif
/* #include <sys/mman.h> */
#ifdef _SYS_MMAN_H_
int __sys_msync(void *, size_t, int);
#endif
/* #include <sys/mount.h> */
#ifdef _SYS_MOUNT_H_
int __sys_fstatfs(int, struct statfs *);
#endif
/* #include <sys/socket.h> */
#ifdef _SYS_SOCKET_H_
int __sys_accept(int, struct sockaddr *, socklen_t *);
int __sys_bind(int, const struct sockaddr *, socklen_t);
int __sys_connect(int, const struct sockaddr *, socklen_t);
int __sys_getpeername(int, struct sockaddr *, socklen_t *);
int __sys_getsockname(int, struct sockaddr *, socklen_t *);
int __sys_getsockopt(int, int, int, void *, socklen_t *);
int __sys_listen(int, int);
ssize_t __sys_recvfrom(int, void *, size_t, int, struct sockaddr *, socklen_t *);
ssize_t __sys_recvmsg(int, struct msghdr *, int);
int __sys_sendfile(int, int, off_t, size_t, struct sf_hdtr *, off_t *, int);
ssize_t __sys_sendmsg(int, const struct msghdr *, int);
ssize_t __sys_sendto(int, const void *,size_t, int, const struct sockaddr *, socklen_t);
int __sys_setsockopt(int, int, int, const void *, socklen_t);
int __sys_shutdown(int, int);
int __sys_socket(int, int, int);
int __sys_socketpair(int, int, int, int *);
#endif
/* #include <sys/stat.h> */
#ifdef _SYS_STAT_H_
int __sys_fchflags(int, u_long);
int __sys_fchmod(int, mode_t);
int __sys_fstat(int, struct stat *);
#endif
/* #include <sys/uio.h> */
#ifdef _SYS_UIO_H_
ssize_t __sys_readv(int, const struct iovec *, int);
ssize_t __sys_writev(int, const struct iovec *, int);
#endif
/* #include <sys/wait.h> */
#ifdef WNOHANG
pid_t __sys_wait4(pid_t, int *, int, struct rusage *);
#endif
/* #include <dirent.h> */
#ifdef _DIRENT_H_
int __sys_getdirentries(int, char *, int, long *);
#endif
/* #include <fcntl.h> */
#ifdef _SYS_FCNTL_H_
int __sys_fcntl(int, int, ...);
int __sys_flock(int, int);
int __sys_open(const char *, int, ...);
#endif
/* #include <poll.h> */
#ifdef _SYS_POLL_H_
int __sys_poll(struct pollfd *, unsigned, int);
#endif
/* #include <signal.h> */
#ifdef _SIGNAL_H_
int __sys_sigaction(int, const struct sigaction *, struct sigaction *);
int __sys_sigaltstack(const struct sigaltstack *, struct sigaltstack *);
int __sys_sigprocmask(int, const sigset_t *, sigset_t *);
int __sys_sigreturn(ucontext_t *);
#endif
/* #include <unistd.h> */
#ifdef _UNISTD_H_
int __sys_close(int);
int __sys_dup(int);
int __sys_dup2(int, int);
int __sys_execve(const char *, char * const *, char * const *);
void __sys_exit(int);
int __sys_fchown(int, uid_t, gid_t);
pid_t __sys_fork(void);
long __sys_fpathconf(int, int);
int __sys_fsync(int);
int __sys_pipe(int *);
ssize_t __sys_read(int, void *, size_t);
ssize_t __sys_write(int, const void *, size_t);
#endif
__END_DECLS
#endif /* !_PTHREAD_PRIVATE_H */